Seat belt anchor mechanism for adjustable seat

ABSTRACT

Seat belt anchor mechanism for vertically movable suspension seat having fore and aft adjustment feature provides an anchor point for a lap belt which is spaced from the floor and movable vertically relative to the floor. The anchor point is carried by a slide on the upper movable seat frame and is movable vertically with the seat suspension but remains stationary when the upper movable seat frame is adjusted fore and aft. Thus, a tether belt connecting the slide to the floor can be kept taut when the suspension is at the upper end of its ride zone, irrespective of the position of the seat in a fore and aft direction. The mechanism includes a plurality of pivot links which are related to each other in such a manner that the anchor point for the lap belt has no horizontal component of movement as the seat suspension goes up and down through its entire movement range.

United States Patent [1 1 Radke et al.

[ 1 Sept. 11, 1973 SEAT BELT ANCHOR MECHANISM FOR ADJ STABLE SEATPrimary Examiner-Casmir A. Nunberg Attorney-James R. Hoatson, Jr. et al.

[75] Inventors: Arthur 0. Radke; Donald C.

Galbraith, both of Milwaukee, Wis. [57] ABSTRACT [73] Assignee:Universal Oil Products Company, Seat belt anchor mechanism forvertically movable sus- Des Plaines, lll. pension seat having fore andaft adjustment feature provides an anchor point for a lap belt which isspaced [22] Filed' 1971 from the floor and movable vertically relativeto the [2i] Appl. No.: 213,621 floor. The anchor point is carried by aslide on the upper movable seat frame and is movable vertically [52] U SC] 297/385 297/388 248/399 with the seat suspension but remainsstationary when [51] I00 B60; 21/10 B60n 1/00 the upper movable seatframe is adj usted fore and aft. [58] Field of Search 248/37; 378 399Thus, a tether-belt connecting the slide to the floor can 248/419 bekept taut when the suspension is at the upper end of I its ride zone,irrespective of the position of the seat in 296/65 74/469 zsol-lso 9 B afore and aft direction. The mechanism includes a plu- Y rality of pivotlinks which are related to each other in [561' References Cited such amanner that the anchor point for the lap belt has UNITED STATES PATENTSno horizontal component of movement as the seat susl f i'i fi 8| pensiongoes up and down through its entire movement o r eta. 2 l 3,109,621ll/l963 Simons et al. 248/399 range 4 Claims, 4 Drawing Figures /20 34.7 //4- "6 W32 if] 4335-; i A //6 I45 '-.r.i M6 11*;:;- L

I48 I58 80 /55 57 M7 SEAT BELT ANCHOR MECHANISM FOR ADJUSTABLE SEATBACKGROUND OF THE INVENTION This invention relates to an anchormechanism for a seat belt and more particularly, to such a mechanism foruse with a'suspension seat having a large amount of vertical travel forisolating the occupant from shocks and vibrations, and substantialhorizontal travel for adjusting the position of the seat fore and aft tothe position most comfortable to a particular occupant.

Although the conventional floor mounting for a seat belt is quitesatisfactory for an automobile wherein the seat permits a very limiteddegree of vertical motion, it is not satisfactory for use with asuspension seat which generally provides four or more inches of verticaltravel. In suspension seats, it has been common to anchor the lap beltto the side of the movable frame of the seat and then anchor the movableseat frame to the floor with a tether belt which is adjusted to be tautin the extreme upper position of the suspension. An example of such amounting can be seen in US. Pat. No. 3,493,211. A problem with the lastmentioned type of mounting arises when the seat is of the type having acapability of being adjusted in a fore and aft direction. Since atypical fore and aft adjustment range for such a seat is about 4 inches,it will be readily appreciated that the movable seat frame to floortether belt must be sufficiently long to accommodate the entire range ofvertical seat movement while the seat'is in its extreme forwardposition. When the seat is in any other fore and aft position, thetether belt will be slack in the uppermostposition of the seatsuspension and therefore incapable of offering any restraint until afterthe seat has been damaged by being moved upwardly beyond its upperlimit.

SUMMARY The seat beltanchor mechanism of the present inven tionovercomes the problem of too much slack in the tether belt by anchoringthe lap belt and connecting the tether belt to a support member which isfree to move up and down with the seat but which is restrained frommoving horizontally at any vertical position of the seat by beingconnected to a pivot linkage which is attached to the floor and to thesupport member. The support member includes a guide portion whichcooperates with a slide member affixed to the movable seat frame topermit the seat and slide member to move horizontally relative to theguide portion so that the seat can be adjusted fore and aft to theposition most comfortable to an occupant without affecting the amount ofslack in the tether belt The slide member also transmits the verticalmotion of the seat frame and suspension to the guide portion which movesup and down with the pivot linkage in a vertical path throughout thevertical movement range of the seat suspension.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side plan view showing theimproved seat belt anchor mechanism except for lap and tether belts, inits installed position attached to a suspension seat (shown in themid-position of its ride zone) and to the floor of a vehicle;

FIG. 2 is a front plan view showing the seat belt anchor mechanism ofFIG. 1 and a fragmentary portion of the seat structure;

FIG. 3 is a front plan view similar to FIG. 2 but eliminating the seatsupport structure and showing the seat belt anchor mechanism with a lapbelt and a floor tether belt attached to it; and

FIG. 4 is a side plan view-similar to FIG. I but eliminating the seatsupport structure and showing the seat belt anchor mechanism attached toa lap belt and a floor mounted tether belt.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. I, theimproved seat belt anchor mechanism is indicated generally at andincludes a guide member 112 which cooperates with slide member 114mounted therein for horizontal movement. The slide member 114 is mountedto the side of the movable seat frame 116 by means of fasteners 118.Mounted on the top of the seat frame 116 is a seat pan 120 which carriesa cushion 121. A back support frame member 122 is pivotally fastened onthe seat frame member 116 and is adapted to support a back cushionmember 123. The seat pan member 120 can move upwardly and downwardly toabsorb vibrations of the vehicle since it is mounted to a suspensionsystem including springs (not shown), a shock absorber (not shown) andfirst and second scissors link members 124, 126

which are pivoted to each other and supported at their I lower ends on amain frame 127 carried by seat track member 180 which is movable foreand aft relative to the floor 146 of the vehicle.

The anchor mechanism 110 includes a 3 bar pivot linkage indicatedgenerally at 111 and a guide member 112 which is slidable horizontallyrelative to slide member 11.4 attached to the upper movable seat supportframe 116. t

Attached to the seat support frame 116 is a seat pan 12 0 carrying acushion 12,1, and a back frame portion 122 carrying a back cushion 123.A seat belt support member 132 is integrally attached to the guidemember 122 such as by welding and includes an upper hole 134 to which aseat belt 166 is attached and a lower hole 136 which carries a supportpin 138 which is held in place by a retainer ring 140. The forward endof an upper link member 144 is pivotally attached to the support member132 by pin 138. The upper link 144 is in turn supported by a lower frontlink 145 and a lower rear link 147' which are attached, respectively, toa linkage support member 148 at pivot connections 155, 157. The linkagesupport member 148 is attached to the floor 146 of the vehicle by meansof floor bolts 158.

The pivot linkage 111 is preferably mounted as shown in FIG. 2 so as tobe positioned under a rear portion of the seat. The links 145 and 147preferably include offset portions to permit the loads applied theretoto be transferred from the pin 138 to the support member148. In thismanner the, elements of the pivot linkage are positioned such that theyare out of the way so that they will not interefere with either the seatoccupant or with the structure under the front of the seat such as thelever 184 which unlocks the seat track.

g In the drawings, the seat suspension and the seat belt anchormechanism 110 are shown in an intermediate position of the 4 inchvertical movement range of the suspension. The dotted line positions ofthe linkage 111 shown in FIGS. 1 and 4 show the lower and upperpositions of the linkage.

Although the lengths of the various links 144, 145 and 147 may bedetermined by trial and error, it is possible to easily determineappropriate lengths of these links to cause the support pin 138 to movein a vertical straight line path. This may be done by causing link 145to have a length between its pivots equal to the vertical movement rangeof the seat, for example 4 inches. The link 147 is then given a lengthof V37? times the adjustment range of 3.464 inches. The link 144 has alength equal to the total of the other two links or 7.464 inches. Thepivot points 155, 157 should also be spaced apart by the length of link145 so that all of the links will lie in line in the lowest seatposition as shown in dotted lines in FIG. 1. If desired, the link 145can also be made of a length greater than the vertical movement range ofthe suspension. in such a case, the link 147 should have a lengthsufficient to reach the upper link and be directed at an angle whichbisects the angle determined by the link 145 and a line connecting pivotpoints 155, 157. Thus, the lap belt 166 will, once tightened for aparticular fore and aft seat position, retain a constant tensionrelative to a seat occupant so that the occupant will be comfortable.

From the preceding description, it will be obvious that the uppermostposition which can be assumed by anchor support pin 138 is the positionillustrated in dotted lines at 138' in FIG. 4. Since the pin 138 doesnot move as the seat is adjusted back and forth to the posi tion mostcomfortable to the seat occupant, the tether belt 170 can be made of anexact length or adjusted to a length so that it will be taut when thesupport pin 138 is at position 138. Thus, in the event of a collision orsudden deceleration, the lap belt 166 will not only firmly anchor theoccupant to the seat frame as it does at all times but will also befirmly anchored to the floor 146 by the tether belt 170 as soon as theseat suspension reaches the top of its travel path. Such an anchorage ismuch more desirable than prior art anchorages in which the tether beltis fixed to the side of the seat and is adjusted to be taut when theseat is in its most forward upper position since the tether belt in suchan anchorage would not be taut in rearward seat positions unless theseat structure had first deformed. Although such prior art anchoragescould also have their tether belts adjusted to a shorter length wherethey would be taut for any fore and aft seat position, the suspensionwould of courseonly be able to travel its full vertical movement rangeat one position of fore and aft adjustment.

A pair of sister hooks 164 on the end of a lap belt 166 mount the lapbelt to an eye bolt 168 fastened through hole 134 in support member 132.The eye bolt 168 is also connected to the upper end of the tether belt170 which has a pair of sister hooks 172 on its upper end and a similarpair of hooks 174 on its lower end which engage an eye bolt 176 mountedon the floor 146 of the vehicle. The lap belt and the tether belt arepreferably made of a web material such as nylon and are conventional.

To provide a capability of fore and aft horizontal adjustment movement,the upper movable seat frame 116 has a seat track member 180 attached toit which rides on and is guided by a floor track member 182 mounted onthe floor 146 of the vehicle. The horizontal adjustment lever 184 isoperated in the usual manner to release the seat track member to adjustthe seat to any desired horizontal position.

We claim as our invention:

1. A seat belt anchor mechanism for a suspension seat having an upperseat support frame movable vertically and horizontally relative to'alower seat frame and to the frame of a vehicle to which the lower seatframe is adapted to be fastened, characterized in that said anchormechanism comprises slide means including a guide member and a slidemember slidable on said guide member, one of said members being fixed tosaid upper seat support frame and the other of said members beingconnected to the lower seat frame by pivot link means comprising anupper pivot link member which is attached at one end to the anchorsupport means, said upper link being attached to the lower seat supportframe by a pair of pivoted links which are of different lengths andwhich are pivotally connected at one of their ends to said lower seatsupport frame and at their opposite ends to the opposite end and to anintermediate portion of said upper pivot link, and seat belt anchorsupport means integral with said other of said members and movabletherewith, said anchor support means being movable vertically inresponse to up and down movements of said upper seat support frame butremaining stationary relative to the lower seat support frame inresponse to horizontal fore and aft adjustment movements of said upperseatsupport frame.

2. A seat belt anchor mechanism in accordance with claim 1 wherein saidpair of pivoted links are mounted to said lower seat support frame atpoints spaced from each other, at least the major portion of the lengthof each of said plurality of pivot link members being positioned at alltimes to the rear of said seat belt anchor support means.

3. A seat belt anchor mechanism in accordance with claim 1 wherein afirst link of said pair of pivoted links is at least as long as thevertical movement range of the seat suspension, the second link of saidpair of pivoted links being spaced from the first link by the length ofthe first link and being connected to said upper pivoted link at a pointlying on a line bisecting the angle formed by the first link and theline connecting the lower pivot points of said first and second links.

4. A seat belt anchor mechanism in accordance with claim 1 wherein afirst link of said pair of links has a length equal to the verticalmovement range of the seat suspension, the second link of said pair hasa length equal to V372 times the length of the first link, the upperlink has a length equal to the combined length of the pair of links, thepair of links have their lower pivots spaced apart by the length of saidfirst link, with the lower pivot point for said first link beingdirectly under the seat belt anchor support means, and said intermediateportion of said upper pivot link being spaced from its ends by distancesequal to the lengths of said first and second links.

1. A seat belt anchor mechanism for a suspension seat having an upperseat support frame movable vertically and horizontally relative to alower seat frame and to the frame of a vehicle to which the lower seatframe is adapted to be fastened, characterized in that said anchormechanism comprises slide means including a guide member and a slidemember slidable on said guide member, one of saId members being fixed tosaid upper seat support frame and the other of said members beingconnected to the lower seat frame by pivot link means comprising anupper pivot link member which is attached at one end to the anchorsupport means, said upper link being attached to the lower seat supportframe by a pair of pivoted links which are of different lengths andwhich are pivotally connected at one of their ends to said lower seatsupport frame and at their opposite ends to the opposite end and to anintermediate portion of said upper pivot link, and seat belt anchorsupport means integral with said other of said members and movabletherewith, said anchor support means being movable vertically inresponse to up and down movements of said upper seat support frame butremaining stationary relative to the lower seat support frame inresponse to horizontal fore and aft adjustment movements of said upperseat support frame.
 2. A seat belt anchor mechanism in accordance withclaim 1 wherein said pair of pivoted links are mounted to said lowerseat support frame at points spaced from each other, at least the majorportion of the length of each of said plurality of pivot link membersbeing positioned at all times to the rear of said seat belt anchorsupport means.
 3. A seat belt anchor mechanism in accordance with claim1 wherein a first link of said pair of pivoted links is at least as longas the vertical movement range of the seat suspension, the second linkof said pair of pivoted links being spaced from the first link by thelength of the first link and being connected to said upper pivoted linkat a point lying on a line bisecting the angle formed by the first linkand the line connecting the lower pivot points of said first and secondlinks.
 4. A seat belt anchor mechanism in accordance with claim 1wherein a first link of said pair of links has a length equal to thevertical movement range of the seat suspension, the second link of saidpair has a length equal to Square Root 3/2 times the length of the firstlink, the upper link has a length equal to the combined length of thepair of links, the pair of links have their lower pivots spaced apart bythe length of said first link, with the lower pivot point for said firstlink being directly under the seat belt anchor support means, and saidintermediate portion of said upper pivot link being spaced from its endsby distances equal to the lengths of said first and second links.